Thread cutting and nipping mechanism for sewing-machines



E. B. ALLEN. THREAD CUTTING AND NIPPING MECHANISMIFOR SEWINGMACHINES.

APPLICATION FILED DEC. 1', 1917.

Patented Feb. 22, 1921.

/54 4 SHEETS-SHEET l- TTORNEY E. B. ALLEN. THREAD CUTTING AND NIPPING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED DEC. 1, 1917. 1,369,371. Patented Feb. 22, 1921.

4 SHEETS-SHEET Z- E. B. ALLEN.

THREAD cumua AND NIPPIN'G MECHANISM FOR sewme MACHINESL I APPLICATIONYHLE'D DEC. 1, 1917.

Patented Feb. 22, 1921.

4 SHEETS-SHEE ,4 TOR/VEY v E. B. ALLEN. THREAD CUTTING AND NIPPING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED DEC.1 1917- 1,369,371 Patented Feb. 22, 192.1.

' SHEET.S5HEET 4- Q Sui M INVENTOR (5am f? QM Yd/27mg /BY M W UNITED STATES PATENT OFFICE.

EDWARD B. ALLEN, OF BRIDGEPORT, CONNEQTICUT, ASSIGNOB. TO THE SINGER MANU- FACTURI NG COMPANY, A CORPORATION OF NEW JERSEY.

'IQHREAD CUTTING AND NIPPING MECHANIlISM FOR SEWING-MACHINES.

Specification of Letters Patent.

Patented Feb. 22, 1921.

Application filed December 1; 1917. Serial No. 204,842.

T 0 all whom it may concern:

Be it known that I, EDWARD B. AnLnN, a citizen of the United States, residing at Bridgeport, in the county of Fa1rfie1d and State of Connecticut, have invented certain new and useful Improvements in Thread Cutting and Nipping Mechanisms for Sew ing-Machines, of which the followlng 1s a specification, reference being had therein to the accompanying drawings.

This invention relates to thread-cutting and nipplng mechanlsm for sewlng machines, more particularly of the buttonhole type such as disclosed in my copending application Serial No. 17,595, filed-March 29, 1915.

It has heretofore been customary at the completion of a buttonhole stitching operation to cut the thread by hand between the eye of the needle and the work and permit the free end of thread, leading from the needle-eye, to hang loosely at the beginning of' a new stitching-operation. While it is possible to sew under this condition, the resuit is unsatisfactory as the free end of the needle-thread is not under control and'is apt to stick out from-the work more or less at the beginning of the sewing. If too short an end of thread is left hanging from the needle-eye, skipped Stitches will result and if too long an end is left hanging from the needle-eye it will project above the work and may be caught up inthe succeed ng stitch-forming cycles by the stitch-forming instrumentalities and result in imperfect and unsightly sewing. In either case where the end of the thread is allowed to hang loosely from the needle-eye, the first few stitches, particularly the first and second,

will be improperly set and will present a loose baggy appearance contrasting unfavorably with the succeeding properly set stitches.

In certain prior constructions the needlethread is held nipped at the upper side of the work prior to stitching. and is released during the formation of the initial stitches by the movement of the work-holder relatively to the machine frame. As thls motion of the work-holder is extremely slow and minute, as compared with the motion of the needle and other stitch-forming instrumentalities, there is great difficulty in accurately timing the release of the needlethread so that the needle-thread end will invariably be drawn down to the same position relative to the upper surfaceof the work. This difiiculty is increased by reason of the intermittent or jerky character of the motion of the work-holder, making it impossible to provide for. the release of the needle-thread endduring the period of the stitch-forming cycle when the work-holder I is stationary. Further than this, the slight amount of lost motion invariably appearingbetween the work-holder and the feeding mechanism permits overthrow of the workholder, particularly since the machine is likely to be subjected to occasional jarring while on the bench. Although these constructions include a fine adjustment for changing the time ,of release of the needlethread, it has; been found impossible by reason of the foregoing to so adjust the devices as to secure uniformity of results under practical operating conditions.

An object of the invention is to provide a sewing machine, particularly a buttonhole sewing machine, with improvedmechanism which will operate to produce uniformly finished seams or buttonholes having properly set beginning andv ending stitches and having no visible thread ends'sticking up above the upper side of the work.

More particularly, the invention has for an object to provide means for holding the beginning end of the needle-thread under positive control during the first portion of the first stitch-forming cycle and releasing said thread-end invariably at the correct predetermined time for it to be drawn down to a practically invisible position, preferably flush with the upper side of the work, by stitch-forming or other thread-handling instrumentalities.

In its preferred form, the invention is embodied in a machine provided with a workholder comprising a lower member and an upper member in the form of a pivotally mounted clamping foot provided with a recess parallel with the work-engaging face of the foot. Within this recess is preferably disposed a combined nippingand cuttingblade operative, respectively, in c'onjunc tion with the upper and lower walls'of said recess. The combined thread-nipping andcutting blade is preferably mounted upon a pivot sustained by the clamping foot and receives its operative thread-nippingandsevering movement from a suitable spring, in opposition to which it is at the proper instant to release the nipped needlethread end by means of a cam-controlled tappet-arm. The blade above referred to is maintained in retracted position by means of a suitable latch which is disengaged at the close of a buttonhole producing cycle to permit said blade to cut and nip the'needlethread under the influence of its actuating spring. The cam-controlled tappet arm is timed to retract the cuttingand nipplngblade to release the nipped. needle-thread end preferably as the needle is rising after its ini-.

tial descent and, in the present instance, after the needle-loop has been seized by the loopcall invisible position, preferably substan tial y flush wit the upper surface of the work.

The invention is shown as embodied in an eyelet-end buttonhole cutting and stitching.

machine :.c0nstructed substantially in accordan'ce with the disclosure in my said pending application Serial No. 17,595. Figures 1 and 2 are perspective views of a machine embodying the invention. Fig. 3 is a vertical section through the bracketarm and bed of the machine looking toward the sup orting standard. 'Fig. 3 is a detail view of in Fig. 3. Fig. 4 is a fragmentary side elevation of a portion of the mechanism as seenffrom the left side of Fig. 3. Fig.4 is

a detail view of the cutterand nipper-:actuating slide-bar and latching means therefor. Figs. 4 and 4 are detail views of portions of the mechanism shown in Fig. 4. Fig. 5 is a development of the cam which effects the properly timed release of the nipper.

Fig. 6 isa top plan View of one of the upper work-clamping members or feet and parts carried thereby. Fig. 7 is a side elevation of the same, partly in section, on the line 6-6, Fig. 6. Fig. 8 is a front elevation of the same. Fig. 9 is a disassembled perspective view of the same. Fig. 10 is a perspective view of the parts closel adjacent the stitching point at the beginning of a stitching cycle before the needle-thread end is released. Fig. 11 is a similar view at a slightly later stage in the stitch-forming cycle after the nipped end of the needlethread has been drawn down to final posi-.

tion.

The machine frame is shown as constructed with the usual hollow-base 1 from the rear end of which rises the standard 2 carrying the overhanging tubular bracketarm a portion of the mechanism shown.

3 terminating in the head 3'. Within suitable bearings 4 is j'ournaled the transverse cutter-shaft 5 disposed in the lower portion of the standard 2. As fully disclosedin my Patent No. 1,048,786, of December 31, 1912, a suitable clutch device is provided for connecting thecutter-shaft 5 with a source of power for a single rotation in each button hole producing cycle. The cutter-shaft 5 is provided with suitable cams 6 and .7 for imparting tilting movements to the cutterlevers 8 and 9.. Mounted within the basel is the usual feed-wheel 10 which imparts the well known lateral and longitudinal components of motionto the work-holder as more fully described in my saidco ending application Serial No. 17 ,595. Thls feedwheel also acts through the usual follower arm 11, vertical shaft 12, arm 13, and link 14 to rock the bellcrank-lever 15, one arm of which is formed with a gear segment 16 meshing with the pinion 17 to rotate the tubular needle-bar 18 in stitching around the eyelet end of a buttonhole and to reverselv rotate the needle-bar to its original position at the endof the sewing operation in the usual manner.

The present work-holder and operated substantially 'in accordance with the disclosure in my copendin application, Serial No. 180,737, filed uly '16, 1917, and comprises the longitudinally traveling slide-plate 19' supporting the crossslide plate or carrier 20 which sustainsv the reciprocally movable lower clamp-plates 21, 21' affording lower work-engaging jaws and supporting the work under the pressure of the clamping feet 22, 22 aifording the upis constructed per work-engaging jaws. The feet 22, 22'

are pivotally connected in a manner well known with the forward ends of the spring clamp-arms 24, 24 having fixed to their rearward endsv by the usual fulcrum pins 25', 25' which arejournaled to rock in. the bearing blocks 26, 26 secured upon the respective clamp-plates 21, 21'. Mounted within. suitable bearings in the blocks26, 26' are the alined rock-shafts27, 27' each provided with a cam acting on its respective clamparms 24:, 24'in opposition to the usual clamplifting springs, one of which is shown at 28. The rock-shafts are connected together for movement in unison by means of the upwardly extending arms 29 and 30, the one being provided with a pin 31 embraced bv the fork 2 of the other. I 5

The present thread-cutting andnipping implements are in many respects similar to those disclosed in my said copending application Serial No. 17,595 and are mounted upon an extension 33 of the clamping foot. 22; Referring to-Figs. 6 to 9 inclusive, the extension 33 will. be seen to include the slightly resilient upper and lower bars 3 1 and 35, rigidly secured together" by the 7 screw 36 and held in spaced relation by guiding the thread to the'nipping point.

a compound thread-nipping andcutting blade. The outer end-portion of the bladesection 41 is formed with an edge-portion 43 inclined abruptly outwardly from the adja-.

cent edge-portion to afford an angle for The edge of the cutting section 42 of the compound thread-nipping andcutting blade is formed beneath the aforesaid angle with a concaved cutting edge 44 which shears the thread against the edge 45 of the ledgerblade 46 let into the upper side of the bar 35. The compound blade 41, 42 is adapted to moveiwithin and substantially fill the space between the bars 34 and 35; the nipping blade 41 coacting with the lower wall of the upper bar 34 in nipping thethread,

While the nipping and cutting elements are preferably constructed in separate sections to facilitate their; manufacture and maintenance in operative condition, it is evident that the blade need not be made in separable sections nor the elements referred to be relatively positioned and connected for operative movement in unison as herein represented.

To operate the nipping and cutting elements, the pin 40 has secured to its upper end the crank-arm 47 whose apertured ex tremity is loosely entered by the screw-pin 48 threaded into the forward end of the cutter-rod 49 which extends rearwardly alongside the clamp-bearing block 26' and passes loosely through the apertured extremity of the supporting arm 50 fixed to the rear side of the block 50' by a screw 50". The block 50 is fixed to the fulcrum-pin 25' by the pin 50 .v Surrounding the rod 49 is a collar 51 a which is secured one end of a tension sp ing 52 the opposite end of which is anchored to said arm- 50. A stop-collar 53 secured to the rod 49 is adapted to strike the arm 50 and arrest the rearward or cutterand nippericlosing movement of the rod 49 under the influence of the spring 52.

The rod 49 is .formed at its underside near its rearward end with a notch 54 affording an abrupt shoulder 55 and an inclined shoulder 56. This notch is adapted to be entered by the extremity of an upwardly spring-pressed latch-lever arm 57 to detain the cutter and nipper elements in their retracted or open position. Secured to the side of the block 50 by the screw 59- and steady pin 59 is the plate 59 havin its upper edge-portion notched at 60 to a ford a stop-shoulder 6,1 engaged by the overhanging lip 62 of the, downwardly springpressed latch-bar 63 pivoted at 64 to the crank-arm 65 fixed to the clamp-closing rock-shaft 27 The lip 62, when engaged with the shoulder. 61, detains the workclamping feet in closed or lowered position and, when the latch-bar 63, is elevated, the

shafts 27 and 27 are free to turnas the clamping feet spring upwardly to release the work. The block 58 serves as a stop to arrest the movement of the crank-arm 65 as the work isreleased. A second overhanging lip 64 on the latch-bar 63 cooperates with the inclined edge-portion'63 of the fixed plate 5.9 to control the vertical position of the bar 63 during the clamp-closing movement of the shaft 27 and insures that the lip 62'will not strike the rear end of the plate 59 but will first contact with the upper edge-portion 66 of said plate before dropping into the notch 60. Thespring 67 surrounding the shaft 27' urges said shaft to clamp-opening position. The latch-bar 63 carriesat its rearward end a vertically adjustab le abutment screw 68,

Secured to the feed-wheel '10 is' a camplate 69 having a cutter tripping rise 70 and a clamp-opening rise 71 which act in succession at the closeof a buttonhole-producing cycle to impart a two-stage lifting move; ment to the arm 72 pivoted at- 73 to the bed 1. The arm 72 has an extension 73 underlying the abutment-screw 68' and carries a I cutter-tripping arm 74 pivoted to the arm 72 at 75 and having its forward slotted end I entered bya screw 76 threaded into the arm "72 to permit adjustment of the arm 74'relatively to the arm 72. The arm 74 has an extension 77 underlying the tail-piece 78 of the latch-lever 57 which detains-the cutting and nipping implements in retracted position. The arm 74 and abutment-screw 68 are preferably s'o adjusted that the cam-rise 70 will'efi'ect the release of the cutting and nipping elements after which the action of the rise 71 will effectthe opening of the work-clamps. The leaf-spring 79 maintains the arm 72 in lowered position.

In the present embodiment ofthe inven-- .tion the following mechanism is provided to effect the automatic release of the threadnipper:-- Y

Secured to the under side of the bracket: arm 3 is a bearing boss 80 in which is journaled a tubular shaft 81 through, which extends a longer solid shaft 82. Formed at one end of the tubular shaft 81 is a short depending arm 83 formed with an arcuate slot 84 entered by a screw 85 threaded into the tappet-arm 86 whose upper end surrounds the shaft 81. The lower end of the tappet-arm 86 is, flattened to engage the rearward end of the rod 49 and push it from dotted to full line position, Fig. 4. Secured tothe other endof the tubular-shaft 81 is an upwardly extending arm 87 formed at its speetively,

upper end with a boss 88 apertured to receive a cam-followerin the form of a plunger-pin 89 whose inner end may be engaged by the groove mounted within the bracket-arm 3 upon the needle-driving shaft 8. The aperture in the boss 88 is enlargedfto receive an expansionspring 92 which surrounds the'pin 89 and at one end bears against a collar 93 on said pin to force the latter yieldingly into the cam-groove 90. -A coiled spring 94 urges the arm '87 toward the abutment block 95 secured to the side of the bracket-arm 3-.

The plunger-pin 89 may be detained in retracted position or out of engagement with the cam-cylinder 91 by means of the spring-actuated latch-arm 96 whose upper extremity is adapted'to enter the notch 97 in said pin 89. The latch-arm 96 is pinned to one end of the solid shaft 82 whose opposite end has secured thereto a depending arm 98 bored out to receive a coiled spring 99 and a pin 100 having a beveled lower extremity and prevented from turning in the arm 98 by means of the screw 101 threaded into .said pin 100 through an elongated aperture 102 in the side of said arm.

The plunger-pin 89 is released and permitted to enter the cam-groove 90 through the action of a lateral projection 103 on a collar 1 03 fixed to thelink 14 which is moved forwardly or in the direction of the arrow, Fig. 4, to effect the customary return rotation of the needle-bar to initial position at the close of a buttonhole-producing cycle. During such movement of the link 14, the projection 103 strikes the pin 100 and rocks the shaft 82 thereby releasing'the plungerpin 89.

The groove 90 of the cam-cylinder 91 is cut with spaced beginning and ending dwell-producing portions 104 and 105, re-

and an inclined portion 106 adapted to shift the plunger-pin 89 rearwardly of the bracket-aim to .open the thread-nipper at the desired time after the machine is started. At the beginning and ending ends of the groove 90 are formed ejecting inclines 104 and 105', the latter of which terminates in a raised surface 107 which ejects the pin the latch 96 to snap into the notch 97 in said pin and hold it in retracted position with its inner end spaced slightly from thecamcylinder. cam-cylinder and" paralleling the ending dwell-producing portion 105 serves to prevent lateral return movement of the pin 89 and arm 87 under the influence of the spring 94 until the pin has been fully ejected'from the cam-groove and latched in ejected posion. v

The stitch-forming mechanism of the machine represented in the drawings is substantially the same as that of my Patent No.

90 in the cam-cylinder 91 89 thereby permitting The flange 108 formed on the shaft 8. The needle 109 forms the depth stitches in the customary manner and presents its loops below the work to the looper 113 which carries them into position to be entered by the usual lower curved and eyepointed needle 114, as shown in Fig. 10.

The needle 114 forms the over-edge stitches as it rises through the buttonhole slit and presents its loops to the needle 109.

The present machine is preferably equipped with the usual stop-motion mechanlsm con'-' structed substantially in accordance with that of my said Patent No. 1,048,786, and including the usual stop-lever 115 carrying at its .extremitythe anti-friction roll 116 adapted to be engaged by the eccentric, outer operative edge 117 of the cam-plate 118 secured by screws 119 to the face of the usual cam-wheel 120 which in machines of thepresent type is' commonly employed for'shifting the fulcrum-block for thebuttonhole cuttingllevers 8 and 9 from retracted to cutting position. The present stop-mechanism also includes the usual loose belt-wheel121 and clutch-ring 122 which serves in a manner well known to clutch said belt-wheel to the lower main-shaft 1'23 to start the machine when the arm 115 is forced downwardly.

The upper thread traverses its usual course from the supply, through the guidepost 124 and tension device 125, thence through the usualapertured guide-elements, one of' which is shown at 126, which present the thread to the spaced rotary take-up disks 127 between which the usual cast-off plate 128 is disposed The thread then leads through the aperture at the top of the post 129 and forwardly to the hollow needle-bar 18 through which the thread descends to the needle 109. Movable across the lead of the thread from the post 129 to the needle-bar 18 is a lateral extension 130 of a pull-off rod 131 slidably (mounted in the head 3 and carrying an extension-piece 132 which projeets outwardly through'a slot 133 in said head 3' and into the slot 134 in the forward extremity of the arm 135 pivoted at 136 to the side of the bracket-arm 3. A lever 137 is also pivoted to the bracket-arm at 136 and comprises a forwardly extending short arm having a slot 138 entered by a screw 139 shifting arm threaded into the arm for the purpose of permitting adjustment of said 'arm 13!) relatively to the lever 137. The downwardly. and rearwardly extended, arm of the lever 137 is disposed above 'a lateral pin 140 carried by thp cutter-lever 8 and serving which embodies the invention in its pre ferred form, and beginning at a point ina buttonhole-producing cycle after the machine has been started and isstitching down 1 the first side of the buttonhole, the plungerpin 89 is detained by the latch-arm- 96 in retracted position and the arm 87 is held against the abutment 95 by thespring 94, thereby detaining the tappet-arm 86 in retracted position, as shown in Fig. 4. The

nipping and cutting elements 41 and 42 are detained in retracted or open position by the engagement of the latch 57 with the shoulder of the notched cutter-rod. 49, as shown in Figs. & and The clamps are closed upon the work and latched as shown in Fig. at.

As the stltch-forming mechanism is 'rotated in stitching around the eyelet-end of the buttonhole, thelink 14 is retracted in opposition to the arrow, Fig. 4, so that the lug 103 is caused to ride past the beveled extremity of the yielding pin 100, and assume the position shown in dotted lines in said figure. After the stitching has progressed down the second side and to one end of the'buttonhole, the stitching action of the stitch-forming instrumentalities is arrested and the further rotation of the feed-cam 10 carries the cam-rise into engagement with the tripping lever 72 to trip the latch 57 thereby releasing the cutter-rod 49 which snaps rearwardly under the influence of the spring 52 and causes the cutting and nipping implements 12 and 41 to sever and nip the needle-thread as shown in Fig. 7; the needle-thread being around the looper 113 when out. Further movement of the feed-wheel causes the cam-rise 71 to effect the second stage of the upward movement of the lever 72 to lift the latch-bar 73 and open the work-clamps. As the work is removed or shifted to a new position, the cut end of the needle-thread leading aroundthe looper to the last stitch will be drawn down below the upper surface of the work.

As the stitch-forming mechanism is reversely rotated to initial position at the close of the buttonhole producing cycle, the projection 103 moving in the direction of the arrow, Fig. 4, strikes the pin 100 and rocks the shaft 82 to withdraw the latcharm 96 from the notch 97 in the plungerrod 89 thereby permitting the spring 92.to force said pin into engagement with the beginning end of the then stationary camgroove 90, as shown in Figs. 3 and When the machine is. restarted after new work has been inserted, the cutter-levers 8 and 9 are advanced during the single rotation of the cutter-shaft to out the button hole slit, thereby drawing down the pulloff bar 130 and measuring the required length of slack-thread from the supply.

The straight needle 109 first rises from the positionshown in Fig. '1 to the top of its stroke and then descends, preferably skipping the first loop of the'curved needle as disclosed in the application of E. B.- Allen and BF. Crosby, Serial No; 106,761, filed June 30,1916. As the needle rises, the

looper 118 seizes the needle-loop and 'presents itto the curved needle, as shown in Fig. 10, While the straight needle rises from the work. In'the present instance, 'at about the time the rising needle-bar 110 and other thread-handlinginstrumentalities have absorbed the measured amount of slack-nee- .dle-thread and said needle-thread is substantially taut, the inclinedportion 106 of the cam-grooves 90 has acted upon the plunger-pin 89 to rock the-tappet-arm 86 03.118?

ing it to strike the rod 49 and rapidly shift said rod forwardly to release the nipped end of the needle-thread loop. The latch 57 snaps intov the notch forming the shoulder 55 of the rod 49 and detains the 'nipper v in open position. In thepresent instance, the still rising needle-bar, the take-up and possibly the looper all act more or less to absorb sufiicient needle-thread to draw down the beginning end thereof to a prac- I tically invisible position preferably substantially'fiush with the upper surface of the work, as shown in Fig. 11.

Preferably during the'second revolution of the needle-bar driving-shaft s, the ejecting incline of the cam-cylinder 91 acts to force the plunger-pin 89 to. inoperative position after which said pin snaps over the end of the flange 108 and'permits return of the arm 87. and parts connected thereto to initial position. v

Although preferable, it is not necessary to release-the initial thread-end during the first reciprocation of the needle as it has been found by experiment that, when the pull is exerted upon the thread leading from .the needle to the work, the essential requirement is that the beginning end-of the needlethread be released before enough stitches.

have been formed to so grip the needlethread that it cannot be drawn down by the thread-absorbing action of the stitchforming or other thread-handling or thread-engaging instrumentalities. It has been found that if the thread is not released before the completion of approximately four stitches it will be gripped so tight by the stitches already formed that it cannot be drawn down by a pull on the thread leading from the needle to the last stitch formed. v

The construction and arrangement of the tinct from various parts are obviously .susce tible of material modification without eparture from the invention.

Having thus'set forth the nature of the invention, what I claim herein-is:.-

41'. In a sewing machine, in combination, stitch-forming mechanism, a work-holder, feeding mechanism movement between the mechanism and work-holder to sew around a buttonhole, means above the work for holding the free end of the needle-thread during the initial descent of the needle, means independent of said feeding mechanism for causing said thread-holding means to release the free end 'oftheneedle-thread after the initial descent of the needle, and means for drawing down the released thread-end to an inconspicuous position.

2. In a sewing machine, in combination, stitch-forming mechanism including a reciprocating needle, a work-support, feeding mechanism for producing step-by-step relative stitchspacingmovement between the stitch-forming mechanism and work-support to sew around a buttonhole, nipping mechanism disposed above said work-support for holding the beginning end of the needle-thread throughout the initial descent of the needle, a power operated tappet disthe work-support and feeding mechanism for striking said nipping mechanism to effect the release of the needle-thread ,end, and mechanism constructed and ar ranged to draw down said needle-thread end to a practically invisible position.

3. In a sewing machine, in' combination, stitch-forming and feeding mechanisms, means above the work for holding the free 'end of the needle-thread during theinitial descent of the needle, a rotary cam operating continuously during the sewing, and means independent of said feeding mechanism and actuated by said rotary cam for effecting the release of the nipped needle thread end before the stitching has progressed far enough to preventthe drawing .down. of the said thread end by the thread-absorbing action of the stitch-forming mechanism.

4. In a sewing machine, the combination of stitch-forming mechanism including a reciprocating needle, of a thread-nipper for holding during .the initial descent of the needle, a rotary cam performing one rotation for each reciprocation of the needle, and automatic throw-out means actuated by said cam for causing said thread-nipper to release the needle-thread during the formation of substantially the first stitch, whereby said thread end may be accurately drawn down to a predetermined position by a pull upon the thread leading from the ,needle to the work.

5. In a sewing machine, the combination for producing relative stitch formin r the free end of the needle-thread with stitch-forming instrumentalities including a reciprocating needle, a loop-taker, a tension adaptedto take up and control-the needlethread during the formation of stitches and pullthread from the supply through said tension device, of nipping mechanism for holding the free end of the needle-thread at the beginning of a sewing operation, and automatic "power-operated means inactive during the major portion of the. stitching operation and acting when thrown into operationto strike said nipping mechanism and effect the release of the free end of the needle-thread at the correct instant of time after the first descent of the needle and during the formation of the first stitch when said thread-handling means have sufiicient remaining thread absorbing action to draw down the beginning end of the needle-thread to a practicallyinvisible position.

6. In a sewing machine, the combination with stitch-forming mechanism including a reciprocating needle, means for holding the beginning end of the needle-thread during the initial descent of the needle, reciprocating pull-off means inactive during the sewing [and operating to render a measured length of slack-thread available at the beginning of a sewing operation, and means for effecting the release ofthe nipped needle-thread end in time for it to be drawn down to a practically invisibleposition.

7. In a buttonhole sewing machine, in combination, stitchforming mechanism, buttonhole cutting mechanism, means for holding the free end of the needle-thread during the initial descent of the needle, means actuated by the buttonhole cutting mechanism for measuring a length of thread from the supply, and means for effecting the release of the nipped needle-thread end device, and thread-handling means before the stitching has progressed far enough to prevent the drawing down of said thread end by the thread-absorbing action of the stitch-forming mechanism.

8. In a sewing machine, in combination,

'and means actuated by said cam for opening said thread-nipper during the formation of the initial stitch to release the needlethread in time for the stitch-forming mechanism to draw down the freeend of said needle-thread to an inconspicuous position.

9. In a sewing machine, in combination,

sewin mechanism includin a reci rocatin D needle, complemental loop-taking means, a

shaft making a plurality of revolutions while the stitch-forming mechanism is in operation, a thread-nipper for holdingthebe-- ginning end of'the needle-thread at the upper side of the work during the initial descent of the'needle, an actuator carried by said shaft, and automatic throw-out connections between said actuator and said nipper for opening the latter at a time during the.

formation of the first stitch such that the stitch-forming mechanism willaot to draw down the free end of the needle-thread to an ing. the beginning end of the needle-thread above the work during the initial descent of the needle, an actuator carried by said shaft, an actuated element stationary during the major portion of the sewing operation and means for establishing operative connections I between said actuator and actuated element to transmit motion to said nipper and release the latter during the formation of the initial stitches.

11. In a buttonhole sewing machine, in combination, stitch-forming mechanism including a reciprocating needle-bar carrying a needle, a main-shaft for the stitch-forming mechanism, mechanism for rotating said needle-bar in stitching around the eyeletend of a buttonhole and for reversely rotating said needle-bar at the end of a button-hole-stitching operation, a thread-nipper for holding the beginning end of the needle-thread, mechanism connected with said main-shaft for opening said threadnipper after the initial descent ofthe needle, means for disconnecting said nipper-opening mechanism from the main-shaft after the nipper has been opened, and devices controlled by said needle-bar-rotating mechanism for reconnecting the nipper-opening mechanism with the main-shaft at the end of a buttonhole producing cycle.

l2.- In a buttonhole sewing machine, .in combination, a stitch-forming mechanism including a reciprocating needle, a needledriving shaft, a thread-nipper for holding the beginning end of the needle-thread, and mechanism operated by said shaft for opening said thread-nipper, said mechanism including a cam, a cam-follower, and automatic means for disconnecting the latter from the cam after the nipper has been opened.

13. In a buttonhole sewing machine, in

combination, a stitch-forming mechanism in cluding a reciprocatin needle, a needle-driving shaft, a thread-nipper for holding the beginning end of the needle-thread, and mechanism operated by. said shaft for opening said thread-nipper, said mechanism including a spring-pressed cam-follower, a

cam having a follower ejectingincline, and a latch for detaining said follower in ejected position.

14. Ina buttonhole sewing machine, in

combination, a frame including a bed and an overhanging bracket-arm, stitch-forming mechanism incorporated insaid frame and including a reciprocating needle, a needledriving shaft, a thread-nipper for holding the beginning endof the needle-thread, and mechanism operated by said shaft for opening said thread-nipper, said mechanism in eluding a nipper-opening lever fulcrumed.

on the bracket arm, an actuating member on the needle-driving shaft,- operative .connections between said nipper-opening lever and actuating membeiyand means for automatically rendering said connections ineffective after the nipper has been opened.

15. In a sewing machine, in combination, sewing mechanism, a -carr1er, reciprocally' movable clamp-plates mounted on said carrier, clamp-armsmounted onsaid clamp.- plates, clamping feet pivotally mounted on said clamp-arms, thread-nipping and severing devices mounted on one of said clamp-- ingfeet, and actuating means constructed. and timed to'cause said devices to nip andsever the needle-thread at the COmPIGtIQIIOf a stitching operation and to release the nipped needle-thread during the formation of the initial stitches of the ensuing stitching operation, whereby the released end of needle thread will be drawn'down to an in-. conspicuous position by the thread absorbing action of the sewing'mechanism.

16. In a sewing machine, in combination, a frame including a bed and an overhanging bracket-arm, stitch-forming mechanism including av reciprocating needle, a workholder, feeding mechanism for producing relative movements between said stitch-forming mechanism and work-holder, a threadnipper located above the work for holding the free end of the needle-thread during the initialdescent of the needle, and power 0perated'means carried by the bracket-arm for opening saidthread-nipper during the formation of the initial stitch to release the needle-thread. v

In testimony whereof, I have signed my name to this specification.

EDWARD B. ALLEN. 

